Furnace.



PATENTED MAY 1, 1906.

A. E. JOHNSON.

FURN ACE.

' APPLICATION FILED JULY 1.1905.

3 SHEETS-SHEET l.

PATENTED MAY 1, 1906.

A. B. JOHNSON. FURNACE.

IAPPLIOATION FILED JULY 1. 1905.

3 SHEETS-SHEET 3.

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PATENT Prion,

ALFRED E. JOHNSON, 0F DENVER, cOLonAoo, ASSIGNORI To THE JOHNSON FURNACE AND". ENGINEERING COMPANY, OF c-OLo- RADO SPRINGS, COLORADO.

FURNACE.

Specification of Letters Patent.

ratented May 1, 1906.

Application filed July 1,1905. Serial No. 267,988.

to make and use the same, reference being.

had to the accompanying drawings, and to the figures of reference marked thereon,

which form a part of this specification.

My invention relates to improvements in furnaces in which only partial combustion takes place in the fuel-bed, the latter being of considerable thickness. In a furnace of this class it is ex'ceedinglyimportant that the nec essary air or oxygen for purposes of combustion shall be united with the unconsumed fuel-gases at theproper temperature and'at the proper point or location where combustion is to ta "e place. In order to attain the desired semigasproducing results, steam is introduced with the air into the chamber below the fuel-bed under suitable pressure to cause theair and steam to pass upwardly through the bed. The steam acts as a combustion-retarding .medium, and by combining it with the air, whose oxygen is a combustionsupporting medium, the desired combination for my purpose is obtainedthatis to say, I get a roper amount of combustion within the fue -bed by reason of the uniono'f the oxygen of the air with the combustible fuel elements, and at the same time by reason of the introduction of the steam with the air undue combustion is prevented, thusproducing a gas and causing a large quantity of unconsumed fuel elements to pass upwardly abovethe fuel-bed, the draft of the furnace having a tendency to carry these elements rearwardly' or to the location where the greatest heat is required. In order to bring about the'desired or necessary union between these unconsumed fuel elements and the air at a proper temperature and at the proper location, I introduce air under pressure to a chamber formed in the furnace-walls around the fire-box and conduct said air through nozzles protruding through the top ofthis chamber and entering recesses or relatively narrow compartments communicating with the tire box at points preferably just above the top of the fuebbed, the said compartments torminating above in a continumls chamber which increases in size as it extendsupwardly, the said chamber being-formed by placing walls on opposite sides of the lire-box, which walls are tapered on the side remote from the fire-box in order to enlarge the air-chamlm-s outside of the fire-box and above the fucl- .bed.' This enlargement is necessary in order to allow the air an opportunity forproper ex ansion after it leaves the compartments beow, thus obviating any back pressure of the air, which otherwise would result, thus preventing the object which I desire to attainnamely, the drawing of the heat from thcfirebox by reason of the suction or partial vacuum produced in the compartments just above the fuel-bed, due to the introduction of air under pressure to said compartments and across the openings communicating with the fire-box, whereby the heatfrom the lire-box is mingled with the' air, thus giving it the proper temperature. As this air is heatedits tendency is to expand, and provision to .ermit this ex ansion is madeb 'the enlar e-- ment of the chamber above, as heretofore explained. both sides of the fire-box and strikes the arch of the furnace, resulting in two opposing currents, which may be said to meet at the con ter of the arch above the fire-box. This meeting of the two currents hasa tendency to throw the air downwardly, and as this air,

while considerably heated, is still cooler than the unconsumed fuel elements rising from the top of the fuel-bed, theair settles downwardly and unites with the rising unconsumed fuel elements, producing the necessary combustion in the upper part of the furnace. In this way I attain an ideal condition and approximate perfect combustion as nearly, I believe, as it is possible to attain this end.

Having briefly outlined my improved construction as well as the function I expect to attain thereb I will proceed to describe the same in detail, reference being made to the accompanying drawings, in which is illustrated an embodiment thereo In the drawings, Figure 1 is a vetical longitudinal section taken centrally through the This heated air passes upwardly on;

I any point forward with an arch 6, which may be suit the special requiren'ients to furnace is to be furnace, the fire-wall, however, being partly broken away on one side to disclose the compartments [into which the air-nozzles protrude. Fig. 2 is a horizontal section taken on the several planes indicated by the line 2 2, Fig. 1. Fig. 3 1s a vertical cross-section taken through the furnace, cutting the fire-box at of the bridge-wall. i is a fragmentary sectional view similar to Fig. 3, but with the parts shown on a larger scale.

The same reference same parts in all the views.

Let thenumeral 5 designate the inclosing walls of the furnace equipped. with buckstays iu-the usual manner and also provided modified to which the applied. The side walls are providedwith chambers 7, which communicate at their rear extremities with a transverse chamber 8, formed in thebridge-wall and whosebottom wall is slotted, as shown at 9, whereby the chamber 8 communicates with a chamber 10 below, into which air is introduced, under pressure This air rising through the slot 9 enters the chamber 8 and passes forwardly through both side chambers 7. The top walls of these chambersZZ are provided with openings in which are inserted nozzles 13, of relatively small diameter and which protrude intorelati'vely nmew compartments or short flues 1%, commencing at the level of the top of the fuelbed and extending upwardly a short distance. These short fines 14 are forined'by placing small partition-walls 15 between the outer wall of the furnace and inner walls 16, preferably composed of fire-clay or other suitable refractory'inaterial. .At the bottom. of these walls areiformed openings 17, leading from the fire-box just above the fuel-bed to the compartments or short lines 14. Above the top flues 14 or above the tops of the partitions 15 thewsurfaces of the adjacent walls 16 are beveled, as shown at 18, whereby the chambersslg, between the walls 16 and the .outer wallsof the furnace, are enlarged to pennit the desired expansion of the air, Whose temperature has been considerably raised by reason of its union with the hot gases drawn from the. top of the fuel-bed by virtue of the suction induced by the introduction of the air under pressure through the nozzles .15 and acrossthe inner extremities of the openings 17 in the fire-wall 16. i I

The necessary air and steam. or the necessary combination of combustion supporting and combustion retarding media is introduced to aclo'sed chamber 20 below the grate 21 ,supporting the fuel-bed. This chamber 20 4 should be sealed, whereby there is'no escape for the fluid introduced thereto except upwardly through the fuel-bed. The airand steam enter the chamber 20 through a duct be readily understood.

characters indicate the from a feed-pipe 12.

erases 22, into which protrudes a nozzle 23, through which the air and steam may be delivered to 4 the duct.

From the foregoing description the use and operation of my improved construction-will The air under pres sure is introduced to the bridge-wall chamher 8 and passing thence into the chambers 7 and upwardly through the nozzles 13 enters the short glues or compartments 1.4. The velocity of the air on entering these lines and passing across theopenings 17, communicating with the lire-box at the top of the fuelbed, is such that it produces suction or a partial vacuum, whereby a portion of the flame or heated gases is drawn through the open- 'ings 17 and uniting with the air so introduced raises its temperature to a point at which it will readily combine 'with the combustible gases that arise from the fuel-bed, as heretofore explained. As this air passes upwardly through the chambers 19, located between the vertical inner walls and the outer walls oi the furnace, the air is mixed thoroughly with the induced current of flame and heated gases, and since the chambers 19 increase in size as the extend upwardly by reason of the taper 18 o the walls 16 the air is allowed the necessary freedom for proper expansion, thus preventing any back pressure, as heretofore explained, which in the absence of the enlargement of the chambers 19. ,The airas it leaves the chambers 19, having an u wardvelocity due to its pressure, tends to ollow the curve. oi the arch, as indicated by the arrows; but as it spreads its motion is checked on each side by the current from the opposite side, whereby it is caused to slowly settle downwardly, where it meets the ascending inflammable gases or unconsumed fuel elements rising from the fuel-bed, thus producing pertect or approximatelypcrfect combustion, and cone sequently intense heat in the upper part of the furnace or wherever the conditions stated are brought about.

In my improved construction of furnace provision, is made for su porting adeep bed of fuel upon a water-coo ed grate. burning of the vfuel in the bed, together ,with the admission of a certain amount of steam with the air, tends toreduce the formation of clinkers, while providing the necessary 'heat for the decon'iposition of the steam and the liberation of the volatile hydrocarbons.

One important result obtained by the ar-' rangementheretofore described for'the in- The slow troduction of air to thefurnace aroundthe fire-box is that by causing the air to flow upwardly against the sides and under the. arch of the furnace these parts are protectedfrom the injurious action of the intense heat pro duced under these conditions. It may bestated that while the temperature of the air is quite high by the time it has reached the in the chambers. anilpartitions located in the bottom of the chambers between the bottom openings in the side walls whereby a series of compartments or fines is formed, and means for introducing air from below and under pressure into the said compartments or fines for the purpose set forth.

.2. A furnace having a chamber located outside ol and above the tops of the Fuel-bed, the said chamber increasing involuzne as it extends upwardly, its top having lree communication with the upper part of the furnace, the said chamber comnmnicating at its bottom with the lire-box by a series of openings above the fuel-bed, partitions separating the bottom of the chamber into a series or compartments correspimrling with the open ings communicating with the fire-box, and up\\'ar(lly-(lirectecl nozzles entering the bottom of the chamber and protruding into the respective compartments in the bottom thereof.

ln testimony whereof I allix my signature in presence of two witnesses.

ALFRED E. JOHNSON.

Witnesses DENA NELSON, A. J. OBRIEN. 

